[61] COLLECTING AND PRESERVING INSECTS RILEY. 



and the larvae are fall grown or nearly so. This holds trne, also, of spe- 

 cies breeding- in seeds and with most leaf-mining species. The greatest 

 difficulty is experienced with carnivorous Coleopterous larvae, and care 

 should he taken with such not to inclose two or more specimens in one 

 box. Most larvae die quickly if placed in an empty box, and this is 

 especially true of predaceous species ; so that it is always advisable to 

 pack the box with moist soil, decaying wood, leaves or other similar 

 substance. Aquatic larvae should be carried in tin boxes filled with 

 wet moss or some water x)lant, for, if placed in corked vials with water, 

 they die quickly. 



Killing Specimens. — Specimens not intended for rearing should be 

 killed immediately after capture unless for each specimen a separate 

 vial or box can be provided. If a number of miscellaneous insects are 

 put in the same vial the stronger specimens will, in a short time, crush 

 or otherwise injure the more delicate ones or the x)redaceous species will 

 devour any others they can master. But even where the specimens 

 are killed immediately the following rule should be observed : Do not 

 put large and small specimens in the same vial, but provide a larger 

 bottle for the larger specimens, and one, or still better, several, smaller 

 vials for the medium-sized and very small specimens. The importance 

 of this rule is recognized by all experienced collectors. 



There are several methods of killing insects, each having its own 

 peculiar advantages and drawbacks. 



Alcohol. — The use of alcohol will, on the whole, prove the most satis- 

 factory method of killing Coleoptera, many Hemlptera, some ISTeurop- 

 tera, and larvae of all sorts. Only the best quality of alcohol should 

 be used, but it should be diluted with from 30 to 40 per cent of pure 

 water, the greatest care being taken to keep the alcohol as clean 

 as possible. During the collecting a mass of debris and dirt is apt to 

 be thrown into the bottle, and when this is the case the alcohol 

 should be changed even during short excursions. At any rate, upon 

 the return from the excursion, the specimens should be at once taken 

 from the bottle and washed in pure alcohol in a shallow vessel. The 

 larvae and other material intended for permanent preservation in alcohol 

 should be transferred to suitable vials and the material to be mounted 

 cleansed with chloroform or acetic ether and then prepared for the 

 cabinet. If it is inconvenient or impossible to mount the Coleoptera, 

 ■etc., soon after the return from the excursion they should be washed, 

 dried, and placed in pill boxes between layers of soft paper, or they may 

 be replaced in a vial with iDure alcohol. On longer collecting trips, 

 lasting several days or weeks, specimens will keej) thus very well, pro- 

 vided they are not shaken up, and this can be prevented by filling the 

 «mpty space in the vial with cotton or soft paper. If the bottle is a 

 large one and contains many large specimens the alcohol should be 

 renewed three or four times at interA?^als of eight or ten days; other- 

 wise the specimens are liable to decompose. Small and delicate speci- 



